Millimeter-Wave Vacuum Electronics Fabrication Facility

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Function
Fabricates millimeter-wave amplifiers based on vacuum electronics, including traveling wave tubes, klystrons, and gyro-klystrons. The fabricated devices are used for research on new ways of generating broadband, high average power millimeter-wave radiation (30-300 GHz frequencies) for emerging radar, EW, and communications applications. The MMW-VEFF also supports research on high current density electron sources and electron beam propagation.

Description
The MMW-VEFF is used to transform theoretical electromagnetic and beam dynamics concepts for devices into functioning real-world prototypes. In a typical process, computer-based solid models of electro-dynamic beam-wave interaction structures are created, based on the theoretical physics design. These solid models are used to generate cutting tool path programs, which in conjunction with the computer-numerically-controlled (CNC) milling machine and lathe, are used to form complex three-dimensional metallic interaction circuits and other component parts. After chemical cleaning, the parts are inspected with a hybrid optical/contact probe coordinate measuring machine. Parts made by CNC mills or lathes are most suitable for Ka-band (26.5-40 GHz) devices. For higher frequencies, including W-band (75-110 GHz), wire and sinker electric discharge machines (EDMs) are typically used in the fabrication process for additional precision. The completed components made by the various techniques are joined together via hydrogen/vacuum brazing using high-purity noble metal alloys. Completed vacuum electronic devices are evacuated, baked-out, and delivered for high-power electromagnetic testing.

Instrumentation
The MMW-VEFF employs a CNC milling machine and a CNC lathe, both having a cutting accuracy of 5 microns. The facility also utilizes wire and sinker EDMs for force-free cutting of metallic structures with 125 micron feature sizes and 2 micron accuracy. A controlled-atmosphere hydrogen/high-vacuum brazing furnace is used for the contamination-free joining of metallic parts, ceramic metallization, and ceramic-to-metal bonding over the 600º to 1700º C temperature range.